HUM 20260727
- Thomas Breckel
- Jul 23
- 11 min read
Updated: Jul 27
Update No. 4
Posted 2:50 pm on Monday, 27
LOW-END TORNADO THREAT ADDED; TRACK REMAINS UNCERTAIN
The National Weather Service in Wilmington has added a low-end tornado threat for this evening. Any tornadoes would most likely be brief spin-ups along the main line of storms and could develop quickly with limited warning.
Damaging straight-line winds remain the primary threat. Large hail, localized heavy rainfall, and isolated flooding are also possible.
Latest Track Information
A complex of thunderstorms is expected to move south from the Great Lakes region this evening. There remains high uncertainty regarding its exact track. Recent model guidance suggests the strongest portion of the complex may remain west of the Interstate 75 corridor, which would reduce the potential for the most significant impacts in Clinton County.
However, the track is not yet certain, and Clinton County remains close enough to the projected storm corridor that residents should continue preparing for possible severe weather.
Primary Timing
The main period of concern is approximately: 6:00 p.m. through midnight
The most likely timing for Clinton County will depend on how the storm complex develops and moves across Indiana and western Ohio.
Updated Hazards
Damaging Winds — Elevated: Scattered downed trees and powerlines remain possible. Stronger portions of the storm complex could produce significant wind gusts.
Tornado — Limited: An isolated, brief spin-up tornado cannot be ruled out along the main line of storms.
Large Hail — Limited: Isolated storms may produce hail capable of damaging vehicles, crops, and outdoor property.
Heavy Rain and Flooding — Limited: Localized heavy rainfall may cause ponding on roads, rapid rises in small streams, and isolated flooding in low-lying or poorly drained areas.
Prepare Now
Residents should use the remaining time to:
Secure loose outdoor items.
Charge phones and backup batteries.
Prepare for possible power outages and blocked roads.
Identify the safest interior room on the lowest floor of a sturdy building.
Maintain multiple ways to receive warnings.
NWS Wilmington is reviewing the latest afternoon model runs and the ongoing storm development in Michigan. Another forecast update is expected after that review. Clinton County EMA will continue monitoring conditions and provide additional information as the storm track becomes clearer.
- - - - END UPDATE No. 4 - - - -
Update No. 3
Posted 5:25 am on Monday, 27 July 2026
Updated 12:26 pm on Monday, 27 July 2026
Bottom-Line Up Front (BLUF): Severe Wind Threat Increasing for This Afternoon and Tonight
Summary
The thunderstorms anticipated overnight remained primarily west of the National Weather Service Wilmington forecast area. Attention now turns to this afternoon and tonight, when at least one organized complex of thunderstorms is expected to move south from the Great Lakes into portions of Indiana and Ohio. New forecast guidance suggests storms could arrive earlier than previously indicated, possibly during the late afternoon or evening. However, confidence remains low regarding the exact timing and track through Clinton County.
Clinton County remains in a Slight Risk—Level 2 of 5—for severe thunderstorms. The county is within the SPC’s 15% severe-wind probability area and the CIG1 conditional-intensity area. Damaging straight-line wind is the primary concern. Heavy rainfall, frequent lightning, and isolated large hail are secondary hazards.
The Enhanced Risk and 30% severe-wind probability area are located farther west and northwest, primarily across western and northwestern Ohio and southeastern Indiana. Clinton County is not currently within that higher probability area. However, the exact path of the expected thunderstorm complex remains uncertain and may shift as storms develop upstream.
Threats
Threats are ranked from highest to lowest concern for Clinton County:
1. Damaging Straight-Line Winds — Primary Threat: An organized thunderstorm complex may produce strong outflow winds capable of bringing down trees and powerlines, causing scattered power outages, blocking roads, and damaging unsecured outdoor objects.
The NWS Wilmington briefing indicates that the strongest portions of the broader storm complex could produce wind gusts greater than 70 mph. This does not mean winds of that strength will occur throughout Clinton County. It means that a higher-end wind event is possible if the strongest part of the complex crosses the county.
The hatching shown over Clinton County is a CIG1 conditional-intensity area. CIG1 is not an additional probability. It indicates that, if severe wind occurs, some wind reports could be stronger than those typically associated with an ordinary severe thunderstorm.
2. Heavy Rainfall and Localized Flooding: A very moist atmosphere will allow thunderstorms to produce heavy rainfall efficiently. Localized flooding is possible where storms produce intense rainfall or repeatedly cross the same locations.
Potential impacts include ponding on roads, water covering low-lying or poor-drainage areas, and quick rises along smaller streams and creeks. The flooding threat is currently considered limited, but locally significant problems could occur beneath the heaviest rainfall.
3. Frequent Lightning: All thunderstorms will contain dangerous lightning. Outdoor activities should be suspended when thunder is heard, even when the storm is not producing a warning or severe-weather damage.
4. Large Hail: Isolated stronger storms may produce hail large enough to damage vehicles, crops, roofs, or other outdoor property. NWS Wilmington currently considers the hail threat limited, with low confidence regarding where hail-producing storms may develop.
5. Tornado: The tornado risk for Clinton County has increased slightly to approximately 2% to 4%. Damaging straight-line winds remain the primary concern, but a brief tornado cannot be ruled out if storms become more organized. The forecast will continue to be monitored for further changes in storm development and organization.
Timeline
Early Monday Morning
Thunderstorms moving through the region early this morning are expected to remain primarily west of the NWS Wilmington forecast area. These storms are not currently expected to represent the primary severe-weather round for Clinton County.
Late Monday Morning through Early Afternoon
Hot and humid conditions will remain in place. Clouds or rain produced by upstream storms could affect daytime temperatures and instability. These details will influence how strong the later thunderstorm complex becomes and where it ultimately tracks.
An isolated storm cannot be ruled out, but the more organized threat is expected later in the day.
Late Monday Afternoon through Evening
This is the earliest reasonable period for an organized complex of strong or severe thunderstorms to approach Clinton County. New guidance supports the possibility of storms arriving during the late afternoon or evening, but there remains considerable disagreement among forecast models.
Residents should not rely on one specific arrival time.
Monday Evening through Overnight
The threat for thunderstorms, damaging winds, heavy rainfall, and lightning may continue through the evening and overnight hours. The timing could shift earlier or later depending on where the storm complex forms, how quickly it organizes, and the direction it travels.
NWS Wilmington currently describes the overall threat window as this afternoon into tonight, with medium confidence in the damaging-wind hazard but low confidence in the exact timing and location.
Additional Information
The forecast remains unusually dependent on how thunderstorms develop several hundred miles upstream. Confidence is high that at least one organized thunderstorm complex will develop and move south from the Great Lakes. Confidence is much lower regarding whether its strongest portion will cross Clinton County, remain west of the county, or track farther east.
The SPC notes that the atmospheric setup contains several characteristics associated with strong, forward-moving thunderstorm complexes. These include substantial moisture, strong instability, and a favorable wind pattern aloft. The eventual path and strength of the complex will become clearer only after storms begin organizing.
Residents and organizations should:
Secure or bring inside objects that could be blown around.
Charge phones and other essential devices.
Have multiple ways to receive warnings.
Be prepared for blocked roads and scattered power outages.
Review shelter locations before storms approach.
Avoid flooded roads and areas with downed trees or powerlines.
Those responsible for outdoor activities, facilities, utilities, transportation, or public events should be prepared to change plans quickly. Storms may move rapidly, leaving limited time between an alert and the arrival of damaging winds.
Clinton County EMA continues weather monitoring and coordination with the National Weather Service in Wilmington. Additional information will be issued as the timing and expected storm track become better defined.
Plan. Prepare. Protect.
- - - - END UPDATE No. 3 - - - -
Update No. 2
Posted 8:40 am on Sunday, 21 July 2026
Summary
The National Weather Service Wilmington is monitoring multiple opportunities for thunderstorms from tonight through Monday night. The first round may approach western Ohio late tonight after developing across the Great Lakes. These storms are expected to weaken as they move south, but an isolated strong or severe storm remains possible. Thunderstorm coverage and intensity tonight remain uncertain.
Monday continues to present the greater concern. Scattered thunderstorms may develop late Monday morning and Monday afternoon, followed by another organized complex of storms moving south into Ohio Monday night. The Storm Prediction Center maintains a SLIGHT Risk—Level 2 of 5—for severe thunderstorms Monday and Monday night, including Clinton County and much of the Ohio Valley. Damaging winds and large hail are the primary severe-weather hazards.
Threats
Threats are currently ranked from highest to lowest concern:
Damaging Straight-Line Winds — The primary hazard, especially Monday night. Stronger storms may produce downed tree limbs, scattered power outages, and isolated property damage. NWS Wilmington identifies an elevated damaging-wind threat Monday for areas north of the Ohio River, with medium forecast confidence.
Frequent Lightning — All thunderstorms will produce dangerous lightning. Outdoor activities may be affected even when storms remain below severe limits.
Large Hail — Large hail is possible with organized storms Monday, particularly during the earlier stages of storm development. The hail threat may decrease if storms consolidate into a larger wind-producing complex.
Heavy Rainfall and Localized Flooding — Repeated rounds of rainfall Monday afternoon through Monday night may cause standing water, rapidly rising creeks or streams, and localized roadway or poor-drainage flooding. The location of the heaviest rainfall remains uncertain.
Tornado — A tornado is not the primary threat for Clinton County. The SPC indicates that any tornado potential Monday will depend on whether individual rotating storms can remain separate, with the more favorable area currently extending from the southern Great Lakes into northern Indiana and possibly western Ohio. Otherwise, less than a 2% risk for Clinton County.
Timeline
Sunday, 26 July — Day 1
MARGINAL Risk (1 out of 5) for Clinton County
Much of the daytime is expected to remain hot and humid.
A complex of storms is expected to develop across the Great Lakes and move southeast.
Scattered thunderstorms may reach western Ohio late tonight.
Storms are expected to weaken while moving south, but an isolated strong or severe storm could produce damaging wind gusts.
Confidence in storm coverage and intensity remains low.
Monday, 27 July — Day 2
SLIGHT Risk (2 out of 5) for Clinton County.
Late Morning through Afternoon: Scattered thunderstorms may develop. Any earlier storms or cloud cover will affect how unstable the atmosphere becomes later in the day.
Monday Evening through Monday Night: This remains the primary period of concern. One or more organized storm complexes may move south or southeast through Indiana and Ohio.
Damaging-wind potential is expected to increase as storms organize Monday evening and night.
Periods of heavy rainfall may continue through Monday night, particularly where storms repeatedly cross the same area.
A precise arrival time for Clinton County cannot yet be established because the timing and track will depend on how storms develop upstream.
Additional Information
The Monday forecast continues to involve substantial uncertainty. Multiple storm clusters may already be underway north and west of Ohio Monday morning. Their location, duration, and associated cloud cover will determine how quickly the atmosphere can recover before additional storms develop.
Several outcomes remain possible:
Overnight storms may weaken before reaching Clinton County.
Late-morning or afternoon storms may develop locally before the main nighttime complex.
Earlier storms and cloud cover may reduce instability and limit the later severe threat.
Sufficient daytime heating may support stronger storms before or during the Monday-night complex.
The primary damaging-wind corridor may shift north or south as storm development becomes clearer.
Residents should have multiple ways to receive warnings and remain weather-aware tonight and throughout Monday. Those responsible for outdoor activities, utilities, transportation, vulnerable facilities, or public events should be prepared to adjust operations when thunder is heard or warnings are issued.
Clinton County EMA continues enhanced weather monitoring and coordination with NWS Wilmington. Additional updates will be issued as storm timing, coverage, and potential impacts become more certain.
Plan. Prepare. Protect.
- - - - END UPDATE No. 1 - - - -
Update No. 1
Posted: 7:30 a.m. on Saturday, 25 July 2026
Updated: 2:40 pm on Saturday, 25 July 2026 (noted in blue)
Summary
The severe-weather potential previously identified for Monday is becoming better defined. Since the initial Heads Up Message was issued, the Storm Prediction Center has introduced DAY 2 (Sunday) and DAY 3 (Monday) outlooks covering portions of the Ohio Valley. Sunday remains a conditional severe-weather day, with thunderstorms expected to develop across the Midwest and Great Lakes that may influence the environment heading into Monday. Monday continues to present the greater concern as one or more organized thunderstorm complexes may develop and move toward Ohio.
The Storm Prediction Center currently places portions of the Ohio Valley within a Slight Risk (Level 2 of 5) for severe thunderstorms on Monday. Clinton County remains within the broader area of concern, with the northern half of the county favored for the greatest potential based on the current outlook. Forecast confidence has increased compared to the original DAY 5 outlook, but uncertainty remains regarding storm timing, exact track, and storm intensity.
Threats
Threats are currently ranked from highest to lowest concern:
Damaging Straight-Line Winds – Primary hazard capable of producing downed trees, scattered power outages, and structural damage.
Large Hail – Stronger storms may produce hail capable of damaging vehicles, roofs, and crops.
Frequent Lightning – Dangerous cloud-to-ground lightning will accompany any thunderstorm.
Heavy Rainfall / Localized Flooding – Localized flooding of roads and low-lying areas is possible where storms repeatedly track over the same locations.
Tornado – There are no indications of a tornado threat at this time. The forecast will continue to be monitored for any changes as storm timing and organization become better defined.
Timeline
Sunday (26 July) – Day 2
General Thunderstorm (0 of 5) for severe weather.
Thunderstorms may develop across portions of the Midwest, Great Lakes, and Ohio Valley.
Any storms affecting Clinton County Sunday are expected to be isolated and conditional.
Sunday's storm evolution will significantly influence Monday's severe-weather potential.
Monday (27 July) – Day 3
SLIGHT Risk (2 of 5) for severe weather.
Morning: Ongoing thunderstorms upstream may influence atmospheric recovery.
Afternoon: Conditions may become increasingly favorable for severe thunderstorm development.
Late Afternoon through Monday Night: Greatest potential for organized severe thunderstorms capable of damaging winds, large hail, frequent lightning, and localized flooding.
Timing will continue to be refined through the weekend.
Additional Information
Forecast confidence has increased since the original Day 5 outlook was issued, but several forecast scenarios remain possible depending on how thunderstorms evolve Sunday and Monday morning. The exact corridor of greatest impact may still shift north or south.
Clinton County EMA continues enhanced weather monitoring and coordination with the National Weather Service Wilmington and the Storm Prediction Center. Additional updates will be issued as forecast confidence improves and operational details become more certain.
Plan. Prepare. Protect.
- - - - END UPDATE No. 1 - - - -
Original Post...
Early Heads Up: Severe Weather Potential Being Monitored for Monday (July 27)
Initial Report Posted 6:50 am on Wednesday, 23 July 2026
Summary
The Storm Prediction Center (SPC) has placed portions of southwest Ohio, including the northern half of Clinton County, within a Day 5 (Monday) severe weather outlook. While confidence in the exact location and intensity of any storms remains low this far in advance, this is the first indication that conditions could become favorable for severe thunderstorms on Monday afternoon or evening.
Residents should not be alarmed by this early outlook. Instead, this is an opportunity to begin paying attention to the forecast as confidence improves over the coming days. Clinton County EMA will continue coordinating with the National Weather Service in Wilmington and will provide updates if the threat becomes more defined.
Current Threats
The exact hazards will become clearer over the next several days, but potential hazards may include:
Damaging wind gusts
Large hail
Frequent lightning
Heavy rainfall
A tornado threat cannot be ruled out this early, but confidence is currently too low to determine if one will develop.
Timing
Monday, July 27: Specific timing has not yet been determined. Additional forecast updates are expected through the weekend.
Forecast Challenges
At five days out, even small changes in the weather pattern can shift the area of greatest concern by many miles. It is too early to determine whether Clinton County will experience severe weather or simply beneficial rainfall.
The Storm Prediction Center's outlook is intended to identify areas where severe weather is possible—not where it is certain to occur.
What You Can Do Now
Review your method for receiving weather warnings.
Stay informed through trusted weather sources.
Monitor updates from Clinton County EMA throughout the weekend as forecast confidence improves.
Plan. Prepare. Protect.
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